Questions tagged [odds-ratio]
A measure of association between two binary variables equal to the odds of a 'positive' outcome in 1 variable divided by the odds in the other. The OR ranges (0, infinity). It has a strong connection to logistic regression.
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ODDS RATIO, NNT CONFUSION
I'm really confused.
I have 3 drugs and the following odds ratios were retrieved -
A 1.71 (95% CI=1.25-2.33)
B 1.58 (95% CI=1.12-2.22)
C 1.48 (95% CI=1.12-1.95)
These values were generated with ...
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Comparing adjusted odds ratios in a model
I have a pretty basic question. Say I run a logistic regression model with 2 variables both dichotomous. falls= sex+stroke+depression. I get 3 different odds ratios, one for males vs females, one for ...
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How to interpret OR confidence intervals for interaction or confounding?
This is a textbook problem I've been trying to understand I wanted to check if my thinking is correct (unfortunately there is no solution manual) I have a case-control study where I'm looking at ...
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COMPARISONS OF ODDS RATIOS
For example, if I have 3 different trials each for 3 different drugs and I used meta analysis (sub group analysis) to generate effect sizes. How can I interpret the effect sizes? All drugs are being ...
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Do small odds ratios observed at multiple time points equate to a large odds ratio when averaged across time points?
I am testing the relative odds of two groups, placebo vs active treatment, guessing that they received active treatment. These guesses were made at four time points, 4, 8, 12, and 24 weeks into a ...
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How to manually calculate odds ratio for continuous variables?
In school, long before learning about logistic models, I've been taught how to calculate odds ratios by hand.
Formula was based on a contingency table, just like this:
This is very easy to ...
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15 views
Re-calibrating Intercept on logistic regression models for unbalance data
I have data-set that I’m modelling using logistic regression as land.cover~H1+H2+H3+H4+H6+H8+H14. My response and categorical variables are binary. However the number of 0 and 1 in my response ...
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Why is information gain rarely used as a reported effect size?
Commonly, in reporting effect sizes in medical articles, papers typically report: risk difference (RD), relative risk (RR) and odds ratio (OR) (and for variable timescale cases and other situations, ...
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How to compute (and report correctly) the signifiance of interaction effect on categorical data, using logistic regression
I want to study the odds of success and failure at some test, depending on gender and some other categorical variables. I calculated the Odds Ratios (OR) of success using Logistic Regression, with « ...
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31 views
Odds Ratio Vs. Risk Ratio
Relative risk, odds ratio, risk ratio, risk difference - these are all measures of the direction and the strength of the association between two categorical variables.
Can I use any of these four ...
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Connection between Hazard Ratios, Survival, and Probability
According to this wiki link, the hazard ratio relates to survival according to the following equation
$$
S_1(t)=S_0(t)^r \quad (1)
$$
where $S$ is the survival and $r$ is the hazard ratio. So from ...
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Using log odds ratio to compare bigram frequency between 2 profiles
I was reading an article where the author proposed using the log odds ratio calculation to compare the relative frequency of bigrams between 2 websites. From my understanding the odds ratios are used ...
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What is the interest to implement a statistics model in a groupby object instead of use the whole groups in a sample?
I saw this topic and also this one in dask documentation.
I wonder what is the real interest to make a model for each group instead of considering a whole sample where all groups would appear? As far ...
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Are effect sizes calculated for prospective/ retrospective cohort studies that look at odds ratios?
Are effect sizes calculated for prospective/ retrospective cohort studies that look at odds ratios? I apologise if this is a silly question
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Is this the correct way to interpret odds ratio for three way interaction?
grateful for any thoughts about this.
I'm doing a generalized linear model analysis of a binomial dependent variable (whether the participant gets the correct answer or not).
I have three ...
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1answer
35 views
Can I use odds ratio in Google trends?
I want to compare the popularity of several fish types:
The way I'm doing it is by using a reference keyword (in this case "fish") and comparing it to whatever fish I'm interested in.
I enter both ...
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How to generate samples from joint distribution of normal and logistic with R?
How to generate triple data $(Y,R,X)$ with R code satisfying following restrictions:
$X \sim N(0,1)$, $R$ is binary and $P(r=1\mid y=0,x) = expit(\alpha_0+\alpha_1 x)$. $Y$ is continuous and $Y\mid r=...
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64 views
Odds Ratio from Linear Regression?
Maybe a stupid question, but can I calculate Odds Ratio's from a linear regression model?
Or is it only possible / allowed on a logistic model?
(I have a linear mixed-effects model and I use r and ...
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32 views
Calculating odds ratio in Multiple select choice question analysis
I have a multiple response categorical variable (MRCV) and a single response categorical variable (SRCV). Respondents in my survey were presented with 6 choices (6 barriers to access an application) ...
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How do I get an odds ratio with McNemar's test?
I have pre and post test data evaluating the effectiveness of a lesson about how to help friends who are being bullied. I am trying to see if more students know how to help a friend being bullied ...
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How to calculate the odds ratio if one of the groups is “0” in a case-control study?
I am using R's epicalc package to calculate the odds ratio. I have these data:
Real values
...
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1answer
172 views
Where is my mistake in this definition of Bayes Factor?
From "The Bayesian Choice" by Christian P. Robert.
The definition of the Bayes factor is given to be the ratio of the posterior probabilities of the null and the alternative hypothesis over the ratio ...
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How does one compute the posterior odds ratio between two models
Apologies if this question has been asked before but I couldn't find anything that matched my problem.
I have some astronomy based data sets and wish to find which of three models fits the data the ...
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3answers
192 views
Computation and Interpretation of Odds Ratio with continuous variables with interaction, in a binary logistic regression model
Question
A binary logistic regression model has been fitted, with the following output;
...
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2answers
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Odds ratio? Can someone help me with what these stats from a paper mean?
this paper I'm reading is on MAOA and violent offenders. From what I understand, an odds ratio of 1.71 means that the violent offenders were almost 2x likely to exhibit the low activity MAOA compared ...
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Conditional logistic regression on matched data with replacement
I'm using 1 to 5 matching on my data with replacement, where each treatment is paired to at most 5 control units with the possibility of one control unit being assigned to more than one treatment.
...
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Adjusted odds ratio question
I have a question about adjusted odds ratios for matched data. Let's assume that we have a binary variable that we want to determine the odds ratios for (let's say smoking or not smoking, this is the ...
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2answers
127 views
17 Week Coin Flip Contest - Calculate Probability/Odds For Each Individual To Have The Winning Count Of “Heads”
I'm new to statistics, like WAY new. So green, in fact, I'm scarcely pushing (0,1,0) in the RGB color model.
I'm presently the recordkeeper for our office's 17-week "Coin flip pool". As of right now, ...
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1answer
257 views
Is meta-analysis of odds ratios essentially hopeless?
In a recent paper Norton et al. (2018)$^{[1]}$ state that
Different odds ratios from the same study cannot be compared when the
statistical models that result in odds ratio estimates have ...
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Can we compare odds ratio from one factor to another factor?
For example ${\rm logit}(\pi)=\beta_1 \cdot x_1+ \beta_2 \cdot x_2$, then I find that the odds ratio of $x_2$ is 27, and the odds ratio of $x_1$ is 1.5, can I say that $x_2$ has a more significant ...
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Difficulty understanding contingency table and logistic regression coefficient
I have the following contingency table
D not-D
E 980 122
not-E 2420 6439
where D may stand for disease, and E for exposure.
This leads to the ...
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1answer
25 views
Difference in logits to difference in probabilities
a) Is there any way to prove that you cannot compute a probability difference when you know a logit difference?
b)In general, is there some acceptable way to convert distances in logodds space to ...
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Odds ratio, Meta-analysis
I have the following for the data for the meta-analysis:
OR , standard errors, logged OR , variance of logged OR
I have generated a forest plots first using "OR" with "variance of logged OR" using ...
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1answer
64 views
Betting with odds
I have a game where I can bet on two teams:
One team has odds $1.7$
The other has $1.5$
I understood that the one that pays off $1.5$ has an higher probability of victory, so it pays less. But how ...
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3answers
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logit - interpreting coefficients as probabilities
I seem to be missing some vital piece of information. I am aware that the coefficient of logistic regression are in log(odds), called logit scale. Therefore to interpret them, ...
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Interpretation of Overlapping p-value = 0 and Odss ratio = Inf
I would like to conduct an enrichment analysis between two lists using GeneOverlap package in R. I am comparing gene IDs from each list, and there is no NAs in there.
This is the code I'm using:
<...
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1answer
32 views
Odds ratio and Risk ratio disagree?
Is it possible for the odds ratio and the risk ratio for a variable to disagree? For example - an odds ratio >1 and risk ratio <1?
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Predicted probabilities for multiple categories of a categorical variable
I'm developing predicted probabilities for hypothetical cases in my glm (binary logit). I have a four category categorical predictor where "Single" is the reference category and "MOU", "JPA" and "AD" ...
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Odds-ratio difference
The odds-ratio denotes a relative effect measure.
If person A has \$100 and person B has \$150, the OR of the
money person B has relative to person A is 1.5. This can be
interpreted as person B ...
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1answer
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Math formula to reproduce a plot comparing Relative Risk to Odds Ratios
I'm trying to reproduce Figures 1, 2 and 3 in this paper (notice that clicking on the FIGURES/TABLES tab is enough to see the plots - no need to sign up or create an account), simply to understand how ...
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1answer
217 views
Does confidence interval for odds ratio assume log-normal distribution?
The formula floating around for calculating 95% confidence interval of an odds ratio is:
e^(log(OR) ± 1.96 x sqrt(1/a + 1/b + 1/c + 1/d))
Does one need to ...
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3answers
776 views
Why is odds ratio an estimate of relative risk?
This link says
In epidemiological terms, the odds ratio is used as a point estimate of the relative risk in retrospective studies.
I understand that odds ratio is calculated in case control ...
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model checking in bayespolr
I'm trying to run an ordered logistic regression with the bayespolr function from the arm package. My response variable is categorical with three outcomes. I've got a few questions about this ...
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Odds ratio formulation of bayes rule for joint conditional distribution
I'm wondering how we can express the marginal conditional odds $O_{h|e}$ when $h$ and $e$ are part of a large joint distribution $P(h,e,z)$.
I know that Bayes rule can be re-expressed in terms of ...
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1answer
179 views
Convert odds ratio to Cohen's d, taking rate of prevalence into account
I am familiar with the generic formula to convert OR to Cohen's d. However, I get the very strong impression from a relatively recent paper (https://www.tandfonline.com/doi/abs/10.1080/...
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39 views
How to assess predictive validity of a variable on the outcome?
I am looking to assess the predictive validity of two measures (M1 and M2) on a binary outcome. After constructing my model, do I just calculate odds ratios and compare the odds ratios for the two ...
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111 views
Crude odds ratio
I came across following definition of crude odds ratio in binary logistic regression:
Crude odds ratio is when you have only one independent variable
And also I heard:
Crude odds ratio is when ...
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How are these odds created?
I've always been a bit baffled by how Vegas creates sports odds. Not so much the process of how did the oddsmakers decide that Option A has odds of X/Y (that obviously is fairly subjective and not ...
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434 views
Rule of thumb for log odds ratios effect size interpretation
Let's start by fitting a logistic model:
fit <- lme4::glmer(vs ~ wt + (1|gear), data=mtcars, family="binomial")
summary(fit)
The output is the following:
<...
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1answer
537 views
Comparison of two odds ratios: Take 2
I would like to test the difference of two odds ratios given the following R-output.
To do so, I would need to take the difference of the log odds and obtain the standard error (outlined here: ...
